The present invention relates to a vacuum insulation body with at least one vacuum-tight casing and with at least one vacuum region which is surrounded by the casing, wherein the casing is provided with at least one opening, in particular with at least one evacuation port, for evacuating the vacuum region, and wherein at least one adsorbent material is present in the vacuum insulation body.
From the prior art it is known to use vacuum insulation bodies for the heat insulation of refrigerators and freezers, which are present in the region between the outer shell of the appliance and the inner container or the inside of the door.
Such vacuum insulation bodies comprise a vacuum-tight casing and at least one vacuum region surrounded by the casing, in which a supporting or core material is present which provides the vacuum insulation body with the required mechanical stability and which in addition prevents that the sides of the casing rest against each other, when a vacuum exists.
Such vacuum insulation bodies are sensitive to an increase of the gas pressure in the vacuum region. Such introduction of gas or such increase of the gas pressure increases the thermal conductivity and thus reduces the effectiveness of the heat insulation body. In particular, due to the higher permeation rates as compared to oxygen and nitrogen, the permeation of water through the casing of the insulation body is decisive for an increase of the thermal conductivity of the vacuum insulation body.
To prevent this phenomenon or keep it as small as possible, it is known to put a material with a high adsorption capacity for water into the vacuum region, in order to keep the partial pressure in the vacuum region low even in the case of penetrating steam. As such material, a zeolite material can be considered, for example.
Furthermore, materials are known which by chemisorption of oxygen and nitrogen keep their partial pressure low. These materials are designated as “getters” and also serve to delay the aging of the vacuum insulation body due to gas entry of these gases.
It is known from the prior art to perform the vacuum generation in the vacuum insulation body in a vacuum chamber, which involves a comparatively high expenditure of apparatus. It is easier to provide the vacuum insulation body with an evacuation port at which negative pressure is applied and through which gas is withdrawn from the vacuum region.
In this case, the entire gas or an essential part of the gas must be removed from the interior space of the vacuum insulation body through the evacuation port. For this purpose, the gas must flow or diffuse through said core material to the evacuation port.